The illustrative embodiments described in the present application are useful in systems including those for tamper detection and more particularly are useful in systems including those for tamper detection and response in electronic modules.
Electronic modules may contain sensitive data that requires protection from unauthorized access. For example, an electronic module may include memory for storing an indication of value such as an electronic vault containing a value of postage. Postage meters containing postage vaults are available from Pitney Bowes Inc. of Stamford Conn.
It may be advantageous for value vaults to be designed to adequately deal with the threat of tampering and fraud in which an attacker may attempt to increase the value stored in the vault without purchasing the postage. An electronic module may contain the only record for a value figure. Such a record may represent an electronic form of value that is equivalent to cash for certain applications such as storing an amount of credit purchased to be used in a vending machine or at a Laundromat. Standards have been developed to test and characterize the ability of such modules to detect and respond to tamper attacks.
Tamper respondent enclosures have been described including certain aspects of tamper respondent enclosures described in U.S. Pat. No. 5,858,500, issued Jan. 12, 1999 to MacPherson, which is incorporated herein by reference. U.S. Pat. No. 5,858,500 describes the use of flexible tamper respondent laminates. U.S. patent application Publication Ser. No. 2002/0,084,090, published Jul. 4, 2002, describes tamper-responding enclosures and is incorporated herein by reference. The prior tamper respondent enclosures utilize a system of wire meshes and wraps surrounding the protected electronics. Low-security devices have been designed with a switch on a door that is used to determine if a clamshell enclosure is opened.